Controversy has surrounded the role exports play in stimulating economic growth. Some authors find causation from exports to GNP, while others have concluded that exports retard GNP growth. Still others find no causation or find bidirectional causation with the Sims test but not with the Granger...

An informal model is described that leads to multiple macroeconomic equilibria as a consequence of random variation in the relative amounts of technological change for new and existing goods. The novel observation is that the rate of introduction and market penetration of new goods vis-a-vis...